1. Field of the Invention
This invention relates to ball valves and more particularly to an inline ball valve of a relatively small outer diameter having no internal voids, when in the open position, and being particularly useful in the food, pharmaceutical and cosmetic industries.
2. Description of the Prior Art
Widely used conventional ball valves are acceptable for general industrial use but for a number of reasons are not satisfactory for food processing, pharmaceutical and cosmetic industries, where high standards of sanitation are mandatory. One reason for this problem is that a valve for general industrial use does not warrant the additional expense of fine surface finishing of valve parts which is necessary to minimize the adherence of material and to facilitate the required frequent cleaning of the valve parts. Another reason is, in the manufacture of valves for general industrial use the valve components must be useful in various valve assemblies to make possible mass production of the components and this results in using more components than necessary in the construction of a single valve. The additional components also make it more difficult to clean the valve. Also, in general use it is permissable for a valve to have sharp corners, crevices, reentrant corners, inaccessible voids and screw threads all of which multiply the cost of a cleaning operation and preclude the use of such valves for food, pharmaceutical and cosmetic industry operations.
U.S. Pat. No. 3,614,056 teaches a flush bottom tank ball valve for use as a bottom outlet on a tank which overcomes many of these objections to prior art ball valves. The ball valve disclosed in U.S. Pat. No. 3,614,056 however requires that a part of the valve be permanently attached to the bottom of the tank. This valve is also of a relatively large diameter which may preclude its use as an inline valve. Another objectionable feature of this flush bottom tank valve is, the valve body does not make flat contact with the ends of the cage parts for maximizing the force pushing the cage parts into high pressure contact with the ball. A further problem with the valve disclosed in U.S. Pat. No. 3,614,056 is that the sealing O-ring is not confined when the valve is removed from the tank bottom.
There is a need in the food, pharmaceutical and cosmetic industries for an inline ball valve of simple construction that has relatively few parts and which provides a smooth, void free passage therethrough. The parts of the valve exposed to the material being conveyed should be corrosion resistant. It is desirable to have an inline valve which is completely free from 90.degree. internal corners and inaccessible voids, crevices, reentrant corners and internal screw threads. It is desirable that the valve be easy to disassemble by hand and be constructed for repeated disassembly and cleaning without damage. It is desirable that the valve have external threaded clamp, or flanged portions for inline use. The valve should be adaptable for use in lines which are closely spaced and run parallel with numerous other lines.